Neutralizing inductive disturbances.



E. F. W. ALEXANDERSUN.

NEUTRALIZING INDUGTIVE DISTUBBANES. l

AMPLIGATIOH FILED APR.2,1913.

i, l 26,992. Patented Bee, 15, w14.

A 2 Pi y @Anf/ a m ww if v @i mating euri-ente the lovv Y ii* lstai'hanees diie to induetion,A onegnetie. rlhus Aneiuetion can e. return einrent hack to i et' returning suoli on through rails.

o be overcome in the use of ie rails into the return e inductive eiteet of the Qenduetor n i t of the Current V Wire at substantially invention is to provide ing: more perfectly than ieen done the induetf e dis- -d in lon' voltage connhase alternating-r current epplceton filed prl 2. i913. Serial No. 758,571.'

interlinked with the trolley-Wire so that substantially the saine amount of current is maintained in adjacent portionsnof both conductors. then establish reactive oonneotions between the rails and the return Conductor so as to properly direct the flow of the Working Current ot the apparatus operating on the system from the rails to the return conductor.

relation between the rails and the return Conductor of such magnitude and direction that the orifing current of the apparatus is directed troni the rails to the return oonfluotor through two paths, and are further designed to proportion the distribution oic current between these paths inversely es the distance ot the apparatus from the reactive connections The novel 'features which believe to oe patent-alii" characteristic of my invention are delinitely indicated in the elainis :ippended hereto.

rfhe features of construction and the inode ot operation of my invention will be understood by reference to the following descrip- These reactive conneo-` tions are designed to maintain a potential tion taken in connection with the accompanying drawings, in Whioliz-h figure l is :i diagrammatic View of a railway system, embodying my invention; l'ig. 21s a. similar View showing a preferred terni of my invention; and Fig. 3 is e glrf'zlhie representation of the .folteges of the inein Conductors of the s ilfsteno..

Referring first to l ef the drawings, have illustrated an electric ear 5 arranged te run en rails 6, only one side of ti e treclr @sing shown. The is provided with e treiley any desired type which oje'ie tively engages the overhead troliey-Wire if will be understood theft the tifpe ni? elecy l Car WliiciA l here shown in the drawings l predetermined length and adjacent sections are connected in seriesthrough the primary Winding 10 of av transformer. The return conductor is similarly divided into sections whic are similarly connected through the secondary windings 11 of the transformers.

Reactances 12 connect the rails 6 lto the returnconductor, and'these reactances 'are located` near to and on eachside of each transfor-mer. I preferably provide one or more` intermediate reactive connections 13 between the rails and the return conductor. A .current lflowing in theoutgoing conductor 7 will, 'in flowing through the primary winding 10 of the transformer, induce a certain current inthe secondary Winding 11 of the transformer, and this induced current will tend to flow through the return conductor 8. The secondary Winding of the trans.

- former has the Same number of turns as the primary winding, and hence the current flowing in the secondary Winding will be substantially the Same as that flowing in the primary Winding. The reactances 12 and 13 provide tWo paths for the flpwof the working currentJ employed to operate a car 5, or other apparatus, from the rails to the return conductor. Vhen a car isoperating on a part of the system between a reactance 12 and a reacta'nce 13, a portion of the working current will ioW from, the rails to the return conductor through reactance 12 and the remainder of the current will similarly flow through reactance 13. The reactances are so designed that the ratio of the amounts of current iowing inpthese respective paths is inversely proportional to vthe distances of the car from the reactances. The reactances are further designed to become magnetically saturated when. a predetermined current fiows therethrough. lVhile magnetically saturated the impedance of the reactance is relatively low, that is, the impedance of the reactance vto the iiow of current in excess of the predetermined amount required toproduce saturation is low compared to the impedance of the reactance to the fiow ofthe predetermined current itself; The. inductance of each reactance and the predetermined current required to produce magnetic saturation of the reactance are proportioned to establish the proper and desired potential relations betweer the rails and the return conductor and also to provide a path of relatively low impedance to the flow of the greater portion of the working current of each apparatus. j

It will be noticed that the arrangement of the reactances 12 in Fig. 1 of the drawings amounts substantially to shunting the vsecondary winding' of each transformer by an inductive winding and connecting the middle point of the latter winding to the rails. It will be evident that the same result can be obtained by eliminating this inductive winding and connecting the middle point of the secondary winding of each transformer to the rails. This arrangement is illustrated in Fig. 2 of the drawings and constitutes a preferred embodiment of my invention. In the arrangement of this gure the middle point of the secondary winding 1 1 of each transformer kis connected to the rails 6 through conductors 141. The conductors 14 and the reactances 13 thus provide two paths for the flow of the working current of any apparatus, operating between a conductor and a reactance, from the rails'to the ret-urn conductor. The reactances and transformers are so designed that the current will divide between these paths, inversely as the distance of the car from'the points of connection between the rails and the return conductor.

The potential relations of the conductors of my improved system will be understood by reference to Fig. 3 of the drawings. The supply station is assumed to be located on the left of the figure. The horizontal line A represents the voltage of the rails which \is that of the ground, and consequently zero. The dotted line B represents the voltage of the outgoing conductor when no transformers are employed, and the line C represents the voltage of the outgoing conductor in my system when transformers are used, as hereinbefore described. The dotted line D represents the voltage of the return conductor, provided the current was returned entirely through such conductor without any ground or rail connections. The line E represents the voltage in the return con ductor'of my improved system. At about the middle portion of each section of the return conductorthe voltage of the conductor is substantially zero and this point is connected through a reactance 13 to the rail. The adjacent ends of the adjacent sections of the return conductor are connected in series through the secondary' windings 11 of the transformers, and the potential difference between these ends is equal to the potential drop in the secondary winding. The middle portion of eaclf secondary winding is connected to ground, either directly as in Fig. 2, or indirectly by means of the shunting reactances as in Fig. 1, and therefore one end of eachsection of the return conductor will be at a higher potential than Freund the adjacent end of the adjacent r will be at a lower potential than f current in 'the rails will, therefore, flow from the rails to that section of the return conductor whose end is at a lower potential than the ground.

lt will noticed from an inspection of ige. l and 2 of the drawings that two paths are provided for the flow of the working` current from the rails to the return conductor. Since/1 the reactive connections between the rails and the return conductor are preferably magnetically saturated by a small portion of the working current, the impedance of these paths is relatively low for the remainder of the working current,

d due to the potential relations mained between the rai-ls and the return conc'cor suoli current will readily flow from the rails to the return conductor.

The particular advantage of my system results om the use of the reactive connections "een the rails and the return conihe use of this character of conductor. neet-ion provides a convenient and efficient means for inaintaininl the proper potential relations between the rails and the return conductor. At the same time the magnetic characteristics vof the reactive connections an be so designed that the current carried ils from the operating` apparatus scent reactive connections will pro-iinately inverse proportion 'ance of such apparatus from the reactive connections, whereby the fleet of these currents is coinnentralized. y

libe obvious to' those skilled in the hat my invention can be carried out by various arrangements differing in form from t `ose herein illustrated and described. ll do noiJ therefore, desire to limit myself to the particular construction or arrangement herein shown, but aim in the appended claims to cor-er a1 modifications which are within the scope of my invention.

lid F claim new and desire to secure by Le s frat-cnt of the United States is:--

i l. in electric railway system comprising, in combination rails forming a continuous conductor, 'an outgoing conductor, a return conduct r, transformers each having a primary winding and fa secondary' winding, one winding of each transformer being connected in series wit-h the outgoing conductor and the other winding of each transformer being connected in series with .the return conductor, and' means for establishing reactiye connections between the rails and the -'1 return conductoi: at points near the transformers..- c

Q. in electric railway system comprising in combination rails forming a continuous conductor system, an outgcire conductor, a return conaooaratus to be o erated on said 7 i ductor, transformers each having a primary winding,` and a secondary finding, one winding of each transformer' being connected in series with the outgoing conductor and the other winding of 4each transformer being connected Ain series with the return conductor, and means for establishing reactive connections between the rails and the return conductor, said reactive connections providing two paths for the flow of the working current of any -operating apparatus from the rails to the return conductor.

3, in electric railway system comprising in combination rails forming a continuous conductor, apparatus to be operated on said system, an outgoing conductor, a return conductor, transformers each having a primary windingand a secondary winding, one winding of each transformer being connected in series with the outgoing conductor and the other 'winding of each transformer being connected in series with the return con- V ductor, and means for establishing reactive connections between the rails and the return conductor, said reactive connections providing two paths for the iiow of the working current of any operating apparatus from the rails to the return conductor and adapted to proportion the distribution of current between these paths inversely as the distance of the apparatus from the reactive connections.

el. in electric railway in combination rails forming' a continuous conductor, apparatus to be operated on said system, an outgoing conductor, a return conductor, transformers each having a primary winding and a secondary winding, one winding of each transformer beingY connectedin series with the outgoing` conductor and the other winding of each transformer being connected in series with the return conductor, and means for establishing reactive connections between the rails and the return conductor at 'points near the transformers, said reactive connections offering paths 4of relatively low impedance to system comprising ratus from the rails to the return conductor;

5. An electric railway system comprising in combination rails forming,r a continuous conductor, apparatus to be operated on said system, an outgoing conductor, a return conductor, transformers each having' a primary winding and a secondary winding, one l the flow of the working' currentof the appa-,

rent of anyapparatus is directed from the rails into the return conductor through tWo -magnetically saturated when the Working current lof any operating apparatus Hows therethrough.

7. An electric railway system comprisingr in combination rails forming a continuous conductor, an outgoing conductor, a return conductor, transformers each having a primary Winding and a secondary Winding, the primary Winding of each transformer being connected in series with the outgoing conductor and theA secondary Winding; of each transformer being connected in series with the return conductor, and means electrically connecting' the middle point of the secondary Winding of each transformer to the rails. l

8. An electric railway system comprising in combination rails forming a continuous conductor, an outgoing conductor, a return conductor, transformers each having aprimary Windingr and a secondary Winding, the primary Winding of each transformer being` connected in series with the outgoing conductor and the secondary Winding of each transformer beingronnected in series With the return conductor, means electrically connectingthe middle point of the secondary Winding of each transformer to the rails, and an inductive reactance located between adjacent transformers and connecting the rails to the return conductor.

In Witness whereof, I have hereunto set my hand this 1st day of April 1913.

ERNST r. W. ALEXANDERSGN.

lVitnesses:

BENJAHIN B. HULL, HELEN kronn.

Copies of this patent may be obtained for `ve cents each, by addressing the Gommissioner of retentir, Washington, D. C32 

